The present invention relates to lighting fixtures, and relates more particularly to a lighting fixture for use in an aquarium that can be alternatively arranged to hold a single lamp tube or two lamp tubes.
Various lighting fixtures are well known and intensively used in aquariums. FIGS. 1 and 2 show a box-like lighting fixture for aquariums according to the prior art. This structure of box-like lighting fixture comprises a substantially rectangular, box-like housing A defining an upper chamber A1, which receives the electric apparatus, and a lower chamber A2, which receives two lamp tubes B. The lower chamber A2 is an open chamber. When lamp tubes B are installed, the lower chamber A2 is closed by a transparent cover board, which is fastened to the housing A by screws (not shown). However, this structure of box-like lighting fixture has various drawbacks. Because the box-like housing A is made from plastics through an injection molding process and has no air vents for the dissipation of heat, it will become aged and fragile quickly. Because the heads of the screws are disposed outside the housing A, they will soon rust away. Another drawback of this structure of lighting fixture is its poor water-proof effect. When in use, moisture tends to get into the housing A, causing an electric leakage. Because the transparent cover board constantly receives the radiation of the lamp tubes B, its material property will soon be changed and become fragile. When the material property of the transparent cover board is changed, it may affect the quality of water. Still another drawback of this structure of lighting fixture is that the lower chamber A2 is designed specifically for holding one or two lamp tubes, and the consumers do not have the option of taking one or two lamp tubes. Still another drawback of this structure of lighting fixture is its poor light reflecting effect. The peripheral wall of the lower chamber A2 of the housing A is covered with a white object (white paper board, white coating, etc.,). Because the white object fades and wears with use quickly, its light reflecting effect becomes worse. Furthermore, because the lower chamber A2 is made of rectangular shape, the projecting angle of light is limited by the two opposite vertical side walls of the lower chamber A2 (see FIG. 2). In order to provide sufficient intensity of light, more sets of lighting fixtures may be required. However, when more lighting fixtures are installed, the consumption of electric power will be relatively increased.